Abstract The Department of Obstetrics and Gynecology (OB/GYN) at Washington University School of Medicine (WUSM) and the Mentored Training Program in Clinical Investigation (MTPCI) propose an innovative research training program in clinical and reproductive epidemiology, specifically designed to strengthen the links between women's health research and traditional epidemiology. The goal of this T32 Program is to promote the performance of epidemiologic research and clinical trials and the transfer of findings that will benefit the health of women through the development of well-qualified women's health investigators. Fellows will learn to use the range of approaches available in epidemiology to address issues in women's health related to etiology, prevention, treatment, prognosis, clinical economics, technology assessment, medical decision-making, and quality of patient care. The two-year training program consists of: 1) a core curriculum of required courses in clinical epidemiology, research methodology, and biostatistics; 2) three required core seminars: reproductive epidemiology and women's health issues, academic development, and ethical and legal issues in clinical research; 3) elective courses; 4) one-on-one mentorship with a methodologic (primary) mentor and a clinical (secondary) mentor, 5) attendance at and participation in research seminars in the MTPCI; and 6) completion of an independent research project in clinical or reproductive epidemiology. The specific aims of the training program are to: 1) provide in-depth knowledge of the research techniques appropriate to clinical research; 2) provide research experience with mentors in clinical and reproductive epidemiology and women's health research; and 3) bring together faculty and fellows through participation in a seminar series that combines expertise in reproductive epidemiology with mentoring in obstetrics, gynecology, and women's health research. Trainees will matriculate in the Master of Science in Clinical Investigation (MSCI), Master of Public Health, or Master of Population Health Sciences degree programs. Strengths of the proposed program are: 1) the long history of successful research training programs at WUSM; 2) the comprehensive course offerings and research programs available to trainees, 3) a history of collaborative links already forged between the WUSM and the Department of OB/GYN; 4) the extensive successful training records of the program directors and faculty; and 5) the resources available to trainees through the WUSM Clinical and Translational Science Award. This T32 program will bring together faculty in the MTPCI and the Department of OB/GYN who have a broad range of rich expertise and a commitment to collaborative research and training, numerous existing large databases that can be used for research projects and training, a broad array of specialized analytic capabilities for clinical studies (e.g., clinical trials, case-control, cohort, etc.), and a successful Division of Clinical Research to provide an ideal environment for this proposed training program.